Cooling-gas circulators for nuclear-reactor power stations

ABSTRACT

A circulator for pressurized gas in the cooling circuit of a nuclear-reactor power station is of a kind having an electric motor mounted in a wall-mounted pressure vessel, and a motordriven blower in the gas space at the inner end of the vessel and including guide vanes pivotally mounted in a gas passage of the impeller casing and adjustable to vary gas flow through the cooling circuit. Vane-adjusting gearing is afforded protection from the gas in the gas space by disposing said gas passage adjacent to the inner end of the vessel and mounting the gearing to extend within the vessel and through the vessel&#39;&#39;s inner end.

United States Patent Cairns et al.

[4 Feb. 15,1972

Ian Norman MacDonald, Largs, both of Scotland [73] Assignee: Jamesl-lowden 81 Company Limited,

Glasgow, Scotland [22] Filed: Oct. 9,1968

[21] Appl.No.: 766,057

[30] Foreign Application Priority Data Oct. 12, 1967 Great Britain..46,803/67 [56] References Cited UNITED STATES PATENTS 1,978,12910/1934 Downs ..415/163 1,988,163 1/1935 Curch..... 2,561,840 7/1951Busquet ..4l5/161 FOREIGN PATENTS OR APPLICATIONS 824,270 11/1959GreatBritain ..415/160 Primary ExaminerRobert M. Walker Attorney-Mason,Fenwick & Lawrence 57 Answer A circulator for pressurized gas in thecooling circuit of a nuclear-reactor power station is of a kind havingan electric motor mounted in a wall-mounted pressure vessel, and amotor-driven blower in the gas space at the inner end of the vessel andincluding guide vanes pivotally mounted in a gas passage of the impellercasing and adjustable to vary gas flow through the cooling circuit.Vane-adjusting gearing is afiorded protection from the gas in the gasspace by disposing said gas passage adjacent to the inner end of thevesel and mounting the gearing to extend within the vessel and throughthe vessels inner end.

2 Claims, 3 Drawing Figures PATENTEBFEB15 r972 3,642,386

sum 1 or 3 l nvenlors Wan-2.0. IQHN Cmrznsk IAN NORMAN Mac DONALDAllorneya PATENTEUFEB 1 5 1972 SHEET 2 BF 3 l I Wanna. Touu fll l tfl gIAN NORMAN MAC. Dosa e 3, ma 4 M W,

5% 1 58 attorneys PATENTEBFEB 15 I972 SHEET 3 UF 3 lnvenlor WALTER.Jen-1N CAlRNS AN NORMAN MAC Donm.

This invention relates to the circulation of cooling gas in the pressurevessel of a nuclear-reactor plant. More particularly, the invention isconcerned with a known gas circulator comprising a tubular housinglocated in an opening in the wall of the pressure vessel to receivecooling gas from the pressure vessel,a motor in the housing, a wallclosing the inner end of the housing to minimize the diffusion of oilmist or vapor from the housing into the pressure vessel, and a blower inthe pressure vessel drivingly connected to the motor. With the motorthus immersed in the cooling gas, the need for a dynamic gas seal forthe motor shaft is avoided.

In this known gas circulator the blower includes an impeller adjacent tothe inner end wall of the housing and guide vanes in the inlet passagemounted on spindles for angular adjustment. Vane control means in thepressure vessel are operatively connected to the vane spindles. The vanecontrol means include meshed toothed wheels on spindles, and bearingsfor the spindles. The toothed wheels and the bearings cannot belubricated as they are in the pressure vessel and lubricant wouldcontaminate the cooling gas. This presents a problem, especially as thecontrol means are required to operate in a high-temperature gas flow. Ithas hitherto been proposed to meet the problem by making the componentsof specially selected materials.

The problem is now met by having (a) the impellers inlet passageadjacent to the inner end wall of the housing, (b) the vane spindlesextending through said end wall, and (c) the vane control means in thehousing and operatively connected to the vane spindles. With the vanecontrol means in the comparatively favorable environment of the motorhousing, they may be formed of conventional materials and may belubricated as required.

Preferably, said gas passage is annular and radially directed, and saidvane means consist of a peripheral series of vanes pivotally mounted insaid passage.

An embodiment of the invention will now be described by way of examplewith reference to the accompanying drawings in which:

FIG. 1 is a sectional side view of a circulator mounted in an opening inthe concrete wall of a power station;

FIG. 2 is a cross-sectional view of the circulator on the line ll-llofFlG. l; and

FIG. 3 is a cross-sectional view of the circulator on the line lll-lllofFlG. 1.

Referring to the drawings:

In a power station of the aforesaid kind having the nuclear core cooledby pressurized gas, a number of main circulators for the pressurized gasare mounted as a peripheral series in the thick concrete wall of acircular concrete building which houses the core and defines a gas space11 of a coolinggas circuit communicating with the core. The manner ofmounting the circulators in the concrete wall 10 is the subject ofcopending Pat. application Ser. No. 766,199. The circulators withdrawgas from a heat exchanger through the gas space 11, and deliver the gasinwards to an annular plenum chamber 12 within the building anddelivering gas to the core. Each cir 6O culator comprises a horizontalcylindrical pressure vessel 13 mounted in a through opening in the wallso that the cylinder 14 lines the through opening, an electric motor 15mounted end-for-end in the vessel, and a centrifugal blower 16 locatedin the gas space 11 and carried by theinner end of the motor 15. Theblowers impeller 17 is keyed to an extension 18 of the motor shaft, andthe impeller casing includes annular radially extending inlet and outletpassages 19 and 20 respectively. The inner end of the motor casingincludes (a) a cylindrical periphery 21 which is a sliding fit in thecylindrical bore 22 of a carrier ring 23 secured within the inner end ofthe cylinder 14, and (b) an annular end wall 24 closing the inner end ofthe cylinder 14 and composed of a center 25 and a hub 26. The periphery21 and end wall 24 together define an annular housing 27 within themotor casing. The impeller casing is secured to the center 25, with theInlet passage 19 adjacent to the center. Annular ducting 28 aligned withthe passages 19, 20 of the impeller casing and discharging into theplenum chamber 12 is secured to the inner end of the cylinder 14.Isolating means for the vessel includes a cover 29 and a bridging ring30 which cooperate with the carrier ring 23 to seal the inner end of thecylinder 14 from the chamber 12 and gas space 11. The isolating meansare the subject of copending Pat. application Ser. No. 766,211. 1

A peripherally spaced series of vanes 31 are pivotally mounted in theannular inlet passage 19. Rotary spindles 32 on the vanes extend throughthe center 24, and their inner ends in the housing 27 are rotatable byactuating means 33 to adjust the vanes angularly and thereby vary thegas flow through the cooling circuit. The spindle-actuating means 33consist of radial anns 34 on the ends of the vane spindles 32, a ring 35oscillatably mounted on the hub 26 and having an upper rim portion 36 inthe form of a rack, a rotary pinion 37 engaging the rack 36, and links38 connecting the ring 35 with the outer ends of the arms 34 so thatrotation of the pinion 37 effects adjustment of the vanes. A drive forthe pinion 37 consists of a stub shaft 39 carrying the pinion androtatable in a boss 40 on the motor casing, a toothed wheel 41 on theend of the stub shaft, an axially extending driving shaft 42 rotatablymounted on top of the motor casing and having at its inner end a toothedwheel 43 meshing with the toothed wheel 41 on the stub shaft, and anelectric motor 44 carried by a casing 45 on the rear end of thecirculator motor 15 and connected to the outer end of the driving shaft42 through gearing 46. Operation of the vena motor 44 effects adjustmentof the angularity of the vanes 31 and corresponding variation in the gasflow through the cooling circuit. An auxiliary drive shaft 47connectedto the vane motor shaft extends through the vessel's outer end closure48 for hand actuation as at 49 outwith the vessel so that the vanes 31may be adjusted without using the vane motor 44.

The spindle-actuating means 33, being thus protectively housing in theclosed pressure vessel 13, are subjected to relatively low temperatures,say about 50 C. as compared with about 300 C. in the cooling circuit,and can be oil-lubricated.

We claim:

1. A gas circulator comprising a tubular housing located in an openingin the wall of the pressure vessel of a nuclear-reactor plant to receivecooling gas from the pressure vessel; a motorin the housing; a wallclosing the inner end of the housing; a blower in the pressure vesselincluding an impeller, and guide vanes in an inlet passage adjacent theinner end wall and mounted on spindles for angular adjustment, thespindles extending through the inner end wall; and vane-control meanslocated in the housing and operatively connected to the vane spindles.

2. A gas circulator according to claim 1, wherein the vanecontrol meansinclude an oscillatable toothed ring, and the inner end wall of thehousing is spaced inwards from the inner end of the motor frame so thatthe wall and frame form a gear chamber, and the wall is composed of acenter portion and a hub portion and the oscillating toothed ring ismounted on the hub portion for oscillation in the chamber.

a a s

1. A gas circulator comprising a tubular housing located in an openingin the wall of the pressure vessel of a nuclear-reactor plant to receivecooling gas from the pressure vessel; a motor in the housing; a wallclosing the inner end of the housinG; a blower in the pressure vesselincluding an impeller, and guide vanes in an inlet passage adjacent theinner end wall and mounted on spindles for angular adjustment, thespindles extending through the inner end wall; and vane-control meanslocated in the housing and operatively connected to the vane spindles.2. A gas circulator according to claim 1, wherein the vane-control meansinclude an oscillatable toothed ring, and the inner end wall of thehousing is spaced inwards from the inner end of the motor frame so thatthe wall and frame form a gear chamber, and the wall is composed of acenter portion and a hub portion and the oscillating toothed ring ismounted on the hub portion for oscillation in the chamber.